Baked egg tolerance: is it possible to predict? / Tolerância aos alimentos assados com ovo: é possível prever quem são esses pacientes?

Abstract Objective: To assess the frequency of baked egg tolerance in IgE-mediated egg allergy patients through the oral food challenge and to assess the tolerance predictability of different skin prick tests, as well as specific serum IgE measurement to egg proteins. Methods: In this cross-sectional study, 42 patients with a diagnosis of egg allergy were submitted to different skin prick tests with egg (in natura, boiled, muffin, ovalbumin, and ovomucoid), and specific IgE to egg white, ovalbumin, and ovomucoid; as well as to the oral food challenge with food containing egg, extensively baked in a wheat matrix. Results: Of the total, 66.6% of patients tolerated the ingestion of egg-containing foods in the oral food challenge. A comparative analysis with positive and negative oral food challenge found no significant differences regarding age, gender, other food allergies, or even specific skin prick tests and IgE values between the groups. Conclusions: The study demonstrated an elevated frequency of baked egg food-tolerant individuals among egg allergy patients. None of the tested markers, skin prick tests, or specific IgE, were shown to be good predictors for identifying baked egg-tolerant patients. The oral food challenge with egg baked in a matrix is central to demonstrate tolerance and the early introduction of baked foods, improving patients' and families' quality of life and nutrient intake.

Resumo Objetivo: Avaliar a frequência de tolerância a alimentos assados com ovo em pacientes com alergia ao ovo mediada por IgE por meio do teste de provocação oral e verificar a capacidade de predição de tolerância ao ovo por meio de teste cutâneo de leitura imediata (Skin Prick Test ou SPT) e de dosagem sérica de IgE específica para componentes do ovo. Métodos: Estudo transversal, 42 pacientes com diagnóstico de alergia ao ovo foram submetidos a SPT com ovo (in natura, cozido, bolinho, ovoalbumina e ovomucoide), IgE específica para clara de ovo, ovoalbumina e ovomucoide e ao teste de provocação oral com alimento com ovo extensamente assado em matriz de trigo. Resultados: Dos pacientes, 66,6% toleraram a ingestão do alimento com ovo durante o teste de provocação oral. Não encontramos diferenças em relação a idade, gênero, outras alergias alimentares ou mesmo entre os valores dos SPT e IgE específica na análise comparativa entre os grupos com teste de provocação oral positivo e teste de provocação oral negativo. Conclusões: Foi demonstrada uma elevada frequência de indivíduos tolerantes a ingestão de alimentos assados com ovo entre os pacientes com alergia a ovo mediada por IgE. Nenhum dos marcadores testados, SPT ou IgE específica, demonstrou ser bom preditor para identificar os pacientes tolerantes. Consideramos que os testes de provocação oral com alimentos com ovo assado sejam fundamentais para a introdução desses assados, melhorar a qualidade de vida e a ingestão de nutrientes dos pacientes e famílias.

Alergia a la leche y al huevo: diagnóstico, manejo e implicaciones en América Latina / Milk and egg allergy: Diagnosis, management and implications for Latin America

La sensibilización a alimentos y el desarrollo de alergias alimentarias viene aumentando en todo el mundo, siendo la leche de vaca y el huevo de gallina los principales alimentos implicados. En la mayoría de los países latinoamericanos no existen guías de manejo y cuando se elaboren deberán adaptarse a las condiciones de la población de cada región. En el presente artículo presentamos una revisión del manejo de la alergia alimentaria a la leche y al huevo útil para el personal de salud de todos los niveles, así como algunas consideraciones de los factores presentes en los países latinoamericanos.

Sensitization to food allergens, as well as the development of food allergies, is increasing worldwide, and cow´s milk and hen´s eggs are the main implicated foods. In most Latin American countries there are no management guidelines on the aforementioned topics; at their creation, such guidelines should be adapted to the conditions of the population in each region. This paper presents a review of the management of food allergy to milk and eggs useful for health personnel at all levels and some considerations of the factors found in Latin American developing countries.

Comparison of Skin Prick Test Results between Crude Allergen Extracts from Foods and Commercial Allergen Extracts in Atopic Dermatitis by Double-Blind Placebo- Controlled Food Challenge for Milk, Egg, and Soybean

Skin Prick Test (SPT's) are performed to identify the causes of allergy. However, low diagnostic accuracy is a limitation to SPT, for which many possible causes have been suggested. The protein composition and allergenicity of crude allergen extracts from foods and commercial allergen extracts for SPT were analyzed. Clinical significances of SPT using crude allergen extracts from foods were compared with those using commercial allergen extracts. A total of 292 atopic dermatitis patients were involved in this study. Crude allergen extracts were prepared from milk, egg white, egg yolk, and soybean. The protein composition of food allergen extracts and commercial allergen extracts of milk, whole egg, white, egg yolk, and soybean were compared by SDS-PAGE. The allergenicity was tested by the immunoblotting method using immune sera. SPTs were performed using crude and commercial allergen. Double-blind placebo- controlled food challenge (DBPCFC) was performed to verify the SPT results and to compare the clinical significance of crude and commercial allergen extracts. Protein composition differed markedly between crude and commercial allergen extracts. By immunoblotting, crude and commercial allergen extracts showed different allergenicity. The SPT results using crude and commercial allergen extracts showed significant differences. The prevalence of milk, egg and soybean allergy was over 35% in atopic dermatitis. The accuracy of SPT using crude allergen extracts from foods was significantly higher than that using commercial allergen extracts. In the case of soybeans, the result of SPT using commercial allergen extract was clinically insignificant for the prediction of soybean allergy. The source of allergen extract was very important for the appropriate SPT in food allergy. The accuracy of SPT might be improved using the appropriate allergen source for food allergy.